The Arizona sentinel., 1887-06-25
A SUN CLUSTER.
Speculations Concerning a Won
 derful Phenomenon.

uCIAON T G4OASAAOAOAs
 In the constellation Hercules there is compact star cluster well-known to owners of powerful telescopes as one of the most interesting and wonderful phenomena to be found in the heavens. To the naked eye it looks like a faint star. In the telescope it appears as a spherical mass of stars, with short, struggling streams, also composed of stars, radiating from it William Herschel computed the number of stars in this cluster at not less than 14, 600. In the center they appear so com pressed that it is impossible to count them.
 Of course every one of the members of this starry swarm is sun, and as- tronomers have sometimes piqued their imagination by wondering what must be the condition of things pre- vailing in such system of suns, and what results flow from the inevitable laws of gravitation there. Could in- habited worlds exist in a sun cluster?
 A calculation of the probable size of the stars in the cluster in Hercules, and of the average distance which separates one from another. has just been made in England by MT. J. E. Gore. He concludes that they have an average diameter of 45. 900 miles, and that the distance from any star in the cluster to the next star is 5000, GOO, 900 miles.
 Taking Mir. Gore's figures as being probably as near the truth as we can get, little consideration will give us some very interesting results. If the stars in question are only 45, 900 miles in diameter, the surface of each pos sesses an area about one-quarter as great as that of the planet Jupiter. Their distance apart, as calculated by Mir. Gore, is more than twenty times the present distance of Jupiter from the earth. Just now Jupiter shines brighter than any star in our sky, with the exception of Venus. If its disk were reduced to one-quarter of its actual size, and it was removed twenty times as far away as it is, it would become invisible to the naked eye.
 But Jupiter shines only by reflected light, while the stars, being suns, shine with their own light which is enor- mously more brilliant than that of planet So if we wish to get an idea of the amount of light shed by one of these clustered suns in Hercules, we must put a body that shines after the manner of the sun in the place of Jupi- ter. Now, if we should remove the sun to distance of 5000, 900, 900 miles, or, roughly, hundred times as far away as it actually is, it would send us only one ten-thousandth part of the light that we now re- ceive from it Then if we should reduce it to diameter of 45. 900 miles, equal to that of the stars in the Hercules cluster, its light would be re- duced about 360 times more, so that it would then shine to us with only one three-million = six -hundred-thousandth part of the light that it now sheds up- on the earth. This, then, supposing that the intrinsic brilliancy of the stars is the same as that of the sun, would represent the amount of light that one of the stars in the cluster sends to its next neighbor.
 But in order to get a conception of the appearance that such star would with that of the stars in our sky. This comparison involves good deal of un- certainty, owing to the great differ ences in the various estimates that have been made of the brightness of the stars as compared with the sun or moon. Shll we can probably get near enough to the truth for our purpose. Take the bright star Sirius, the most brilliant fixed star in the heavens. Any one who wishes can see it in the south ern heavens early in the evening at this season. Various estimates of the light of Sirius have made it from one twenty-thousand-millionth up to about one five thousand-milliont of the suns light. Suppose we adopt the latter figure as being the most favorable to Sirius. Then comparing this with the fraction representing the light of star in Her cules as seen from its nearest neigh bors in comparison with that of the sun, namely, one three-million-six- hundred-thousandth, we find that the